1. Field of the Invention
The invention relates to a color filter substrate and method of manufacturing the same, and more particularly to a color filter substrate that improves display quality.
2. Discussion of the Related Art
Typically, a liquid crystal display (LCD) apparatus includes an array substrate having thin film transistors (TFTs) arranged thereon, a color filter substrate, and a liquid crystal layer having an anisotropic dielectric constant. The LCD apparatus applies an electric field of controllable intensity to the liquid crystal layer disposed between the array substrate and the color filter substrate for obtaining a desired image signal.
A conventional LCD apparatus includes a first substrate, a second substrate, a liquid crystal layer, and a spacer. The spacer maintains a uniform cell gap between the first substrate and the second substrate. A response time is required to respond between black and white of LCD apparatus. Contrast ratio, viewing angle and brightness uniformity, etc., vary in accordance with a thickness of the liquid crystal layer. The spacer may be formed into a number of different types and shapes, for example, a bead spacer, a column spacer, a conductive spacer, and the like. Generally, the bead spacer may have spherical shape and includes a plastic material having an elasticity. The bead spacer is randomly arranged between the first substrate and the second substrate. The cell gap may be uniformly maintained by increasing the number of bead spacer. However, increased number of bead spacers disturb the alignment of liquid crystal layer, decreasing the image quality of the LCD apparatus.
The column spacer is formed integrally with the first substrate. When manufacturing the first substrate, the position adjustment of the column spacer prevents liquid crystal layer alignment disturbances. However, the column spacer requires an additional photo process (e.g., photolithography process), increasing the manufacturing costs. Also, the column spacer is less elastic than the bead spacer, and thus generating air bubbles as the temperature of liquid crystal layer changes, thereby causing a volume change.
To overcome such problems as described above, Japanese Patent (JP-Heisei 9-292619 entitled “LCD apparatus and method for manufacturing the same” issued to Yamada Satoshi) describes a bead spacer integrally disposed with the black matrix. Additionally, Japanese Patent (JP-Heisei 5-216048 entitled “LCD electro-optic apparatus and method for manufacturing the same” issued to Sugiyama Nobuo) discloses that photoresist and bead spacer are coated and they are selectively removed by a photolithography step to dispose the bead spacer on a predetermined position.
Disclosed solutions have a number of disadvantages. For example, the light-blocking property of the black matrix may become deteriorated as a portion of the light passes through the bead spacer. As a result, the light may leak, thereby deteriorating the contrast ratio and image quality of the display.
Moreover, image quality may deteriorate as the size of a mother substrate is scaled up because of misalignment between a first mother substrate and a second mother substrate reduces.